When thermally cutting a metal plate (hereinafter referred to as “workpiece”) with plasma arc or laser light, molten metal and metal vapor blow off the cut grooves of the workpiece and coagulate, creating dust particles of several hundred microns to several sub-microns (the dust particles created when cutting the steel plate mainly contain iron oxide and such dust particles are hereinafter referred to as “fume”). Since this fume is lightweight, having a specific gravity of 0.5 g/cm3 or less and floats in high-temperature gas, it pollutes the environment of the work site if it is left. Therefore, conventional thermal cutting machines of this type are equipped with a dust collector for collecting the fume suctioned from the inner space of the cutting table through a dust collection duct and, during thermal cutting operation, the dust collector is operated to thereby catch and collect the fume generated during the thermal cutting.
As such a dust collector, a dry-type dust collector is often used in which fine particles are removed from the fume by filtration with a bug filter or adsorbed by an electrode plate. In the dry-type dust collector, the fine particles separated and collected from the fume are once stored in a hopper. Then, they are automatically ejected from the dust collector by means of a rotary valve, screw conveyor or the like. Alternatively, the fine particles are manually scraped out with a shovel etc. and then packed in plastic bags, metal drums, pails etc. for disposal as industrial waste.
In a known technique related to the present invention, fine particles such as cotton dust collected by a dust filter etc. are compressed and solidified into a briquette shape by a pressing machine and then ejected from the system (see Patent Document 1).
Patent Document 1: Japanese Unexamined Patent Application Publication No. 5-230727